Most TV content is transported over the wide-area network by satellite. Content owners and broadcasters feed their live and stored programming into earth stations which uplink the programs over radio frequencies to transponders in satellites, which then broadcast over wide geographic areas (the entire footprint of the satellite). Receiving satellite dishes receive the transmission of the program at cable, telco and other television delivery head-ends. This programming is then transformed into signaling that the existing television delivery infrastructure can transmit and deliver to the home. In addition to providing wide-area feeds to telco, cable and other customers, there are other satellites which provide direct broadcast capability to home satellite dishes (DTH). Both of these forms of satellite transport have the advantage of being a point-to-multipoint system that can efficiently deliver programming to a large number of geographically dispersed subscribers. Both satellite systems however, also have capacity and cost constraints in terms of transmitting a large number of channels. For example, satellite-based transmission is constrained by virtue of limited spectrum available for transmission between ground stations and the satellites, as well as the power that can be packaged into a satellite in space. Also, the number of satellites is limited by cost, launch capability, and available orbits and the number of transponders per satellite is constrained. As a result, all satellite distribution has been for bundled packages with a small number of channels that have very high viewership. Furthermore, satellite video distribution systems only allows for very limited interactivity due to the power and cost required for uplink transmission. As a result, satellite broadcast is often accompanied by a terrestrial return path.
IPTV is a term for television distribution over a private IP network. The implementation of IPTV can take many forms:                An end-to-end IPTV solution where programming is carried over an IP network from the content source to the subscribers home;        IPTV can be an IP segment in an overall system that may consist of satellite, fiber, coax and IPTV;        IPTV can also be used as a subsystem to deliver limited content, such as video on demand;        IPTV removes some of the capacity and interactivity constraints inherent in satellite transmission. IPTV is generally delivered over a private IP network owned by either telecom carriers or cable companies. As a private network it can be viewed as a “walled garden” such that ingress and egress to the network are controlled directly by the carrier who owns the network. No content other than the carrier's content is allowed on the network. The benefit is that contention on the network can be controlled and managed by the carrier simply by allowing or disallowing what appears on the network (it is not a shared facility). Also, as a private network, it offers a more secure and managed form of transport.        
IPTV has not been deployed widely because of cost. Since it is a private network, the telecom carrier or cable company has to incur the cost of creating and maintaining a dedicated IP network. The network has to be built for peak capacity, so that peak capacity then creates a hard constraint on the number of channels that can be offered. If that telco or cable provider is providing Internet service as well as TV, they may need to have two separate IP networks in order to prevent contention. Content providers may typically have to have private links into the IPTV network in order to distribute their content. Finally, a major cost constraint for IPTV to the home is the need for a new set top box.
Hybrid Fiber Coax (HFC) networks are used by both cable and telco television systems to deliver television programming to the home. HFC consists of a fiber and a coax segment where programming comes to a fiber node and is then distributed over several coax loops to different sets of individual homes. Each coax segment has a limited amount of frequency available for broadcast television. Typical frequency ranges can be between 50 and 500 Mhz. Newer systems are capable of going up to 1 Ghz. Digital or analog television programming consumes a certain amount of frequency per stream, which limits the number of linear channels that can be delivered to the home.
An alternative to HFC distribution is Fiber-to-the-Home (FTTH), in this system the fiber node is the individual home, and coax loops are used only inside the home and start at the fiber termination. This implementation removes some of the frequency constraints in coax delivery. FTTH implementation is expensive, and an example of this in the US is Verizon's FIOS network. Even with FTTH, the home network is still coaxial and still has the linear programming constraints that the coax cable has. Also, neither HFC nor FTTH have the capability of carrying tens of thousands of channels to the home in a linear, always on fashion.
Switched Digital Video (SDV) is a technology for distributing television programming to the home on demand. Using SDV, a telco or cable carrier delivers a specific television program to the end subscriber only when that subscriber switches to a specific channel. Unwatched channels are not sent over the HFC or FTTH infrastructure. SDV results in more efficient last-mile bandwidth usage. However, for linear programming, SDV still requires the originating programming to terminate at the carrier's video hub. SDV is also used to deliver stored programming like video-on-demand or pay-per-view. This content is already stored at the video hub. An inherent limitation for SDV technology is the amount of linear and stored programming available at the video hub. Hence, the efficiency gain of an SDV network is actually limited by the amount of content available at the video hub.
Switched multicast and switched unicast are both forms of switched broadcast. In a multicast environment, a subscriber wanting to watch a program already being delivered to a service group simply joins the existing switched session. Switched multicast is the basis of switched broadcast systems being deployed today. In a unicast deployment, each subscriber receives a unique program stream. The benefits of switched unicast include targeted addressable advertising and increasing personalization of content, along with other opportunities for enhancement of subscribers' viewing experiences. Switched broadcast, also known as switched digital broadcast and switched digital video, dramatically reduces the amount of network capacity required to provide subscribers with all the programs they want to watch. Switched broadcast delivers programs only when and where requested by subscribers, unlike legacy broadcast systems that deliver all programming to all subscribers, all the time.
This is accomplished, essentially, by providing a subscriber's STB (set-top box) the ability to communicate with a video hub about which program the subscriber wants to watch in real-time. However, the video hub or head-end still receives all of the content channels from the content sources, without the ability to request content from content sources on demand. For this reason all content sources must transport their content to the video hub or cable head-end. The switched broadcast system responds by delivering to the viewer's service group from the video hub or cable head-end, but not on demand from the content source, only those programs being watched by subscribers within that group, and the STB tunes to the appropriate program. In this way, the content delivery bandwidth of the video hub or cable head-end that would otherwise be needed to deliver unwatched content is reclaimed and switched broadcast offers cable operators the opportunity to expand the amount of the offered programming at the video hub, but not at the content source.
Additional bandwidth savings at the video hub or cable-end are achieved by allowing more than one subscriber within a network node, or service group, to access the same program stream, but not on demand from the content source. If a subscriber wants to watch a program that is currently being delivered to other subscribers within the same node, the new subscriber simply joins the existing switched session at the video-hub or cable head-end. As a result, no additional capacity is consumed by the incremental subscriber at the video-hub or cable head-end. This practice, known as switched multicast, is the basis of switched broadcast systems deployed today.
One of the main drawbacks of the current HFC-based video distribution systems is the lack of selectivity on the part of consumers to choose their own channels of interest directly form the source. Instead, such subscribers are at the mercy of their service providers to provide them with predetermined bundled channels from the video hub or cable head-end according to their agreements with various content providers and/or distribution partners. As a result, consumers are forced to receive content that may not be of interest to them.
Internet television refers to the delivery of television-like programming over the Internet to an Internet connected device at the consumer's home. Internet television has the advantages of scale, cost and ubiquity. The biggest constraint on Internet television is the lack of reliability and quality of service available on the Internet, since it is subject to the packet loss, jitter and delay on the physical Internet. As the Internet is a shared resource, Internet television has to contend with data, video and voice traffic on the public Internet. Another limitation on Internet television is that it is difficult to watch the programming on actual televisions because of technical and user interface challenges. One example of a weakness in the user interface is the lack of an electronic program guide. Also, you need a separate piece of consumer equipment to convert the video packets over the Internet into a television signal that is sent over standard TV cables to the television. Finally, the TV also must be switched to the appropriate input device to select this device instead of the cable set top box or a DVD player.
A specific form of Internet television is Internet video. Internet video is a term for any stored video delivered over the Internet, for example YouTube. The advantage of Internet video is on-demand programming with an almost unlimited amount of programming and easy search methods for specific videos. An advantage of Internet video over Internet television is that it can be delivered reliably by adding delay through buffering, something that is possible because the content is stored and not live. It still has the same disadvantages as other Internet television in terms of how it is displayed on the consumer's TV.
A number of new consumer premise equipment (CPE) devices have been developed that display some forms of video and audio content downloaded from the Internet onto a television. These devices each support different content formats and control methods but they all have a few characteristics in common. They all connect to the user's home network to access the Internet (over wireless 802.11 networks or physical ethernet), and connect directly to one of the TV inputs (S-Video, component cables, HDMI, etc). Some examples of these devices include Apple TV, Roku, Xbox 360, Playstation 3, and Vudu. All of these devices have the limitations described above under Internet television where they require the user to switch their TV input to access the content and they have an interface for searching and selecting content separate from the main cable television program guide. Some of these boxes have a very limited selection of content as they only support a specific set of websites or services (iTunes). These devices also require the consumer to purchase an expensive new box in order to access the content.
Therefore, there exists a need for a more efficient system and method for distribution of video that takes advantage of existing video distribution infrastructure.